Synthesis And Humidity Sensing Properties Of Ba-Sr-Nb-O Perovskite And ZnO

Humidity sensor is closely related with human life and industrial production,which has been widely used in many fields.Since the advent of the alumina sensor in 1941,metal oxide ceramic materials have been extensively studied in the field of humidity sensors,because of their strong thermal stability and anti-pollution.Based on the structure,doping and morphology control of the materials,several kinds of metal oxide materials were prepared and fabricated into humidity sensor prototype devices.The humidity sensing properties were also studied.The experimental results are as follows:1.Synthesis of layered Ba_5-xSr_xNb₄O₁₅ perovskite solid solution and its humidity sensing propertyThe Ba_5-xSr_xNb₄O₁₅ perovskite solid solution was prepared by molten salt method and its structure and morphology were characterized.The effect of substituting A site on humidity sensitivity was studied.The results show that with the increase of strontium content,the unit cell of Ba_5-xSr_xNb₄O₁₅ is gradually decreasing.The sensitivity of the series solid solution increases with the substitution of strontium and reaches the maximum value at Ba₂Sr₃Nb₄O₁₅ and then decreases.The response time of 4 seconds,recovery time of 9 seconds,showing a rapid response recovery performance.Has excellent cycle stability and long-term stability.2.Ba₄Nb₂O₉ molten salt synthesis and humidity sensitivityCubic Ba₄Nb₂O₉ was prepared by molten salt method,its structure and morphology were characterized,and its humidity sensitivity were tested.In the humidity sensitive performance,the response time of 2 seconds,recovery time of 58 seconds.At 95%relative humidity,the sensitivity was 62.48,showing a rapid response recovery performance.3.Hydrothermal synthesis of zinc oxide nanosheets and its humidity sensitivity testThe microstructure and morphology of the ZnO microspheres prepared by hydrothermal method were characterized.The wet tability was tested by AC method.The optimal operating frequency is 100Hz.The response time of zinc oxide humidity sensor is 2 seconds,and the recovery time is about 25 seconds,with excellent cycle stability and long-term stability...